Galvanic cell.



M. L. KAPLAN.

GALVANIC CELL.

APPLICATION HLED NOV. 20, 1914.

Patented Apr. 3,1917.

WITNESSES:

A TTOR/VE Y.

D FATE MOBDUCH jL. KAPLAN, or RnoOKLYN, NEW YORK, AssIeNOR T0 BEACON mmmrena; ELECTRIC Co., INC., or NEW YORK, N. Y., A CORPORATION or NEW YORK.

" GALVANIC CELL.

Application fi1ed November 20, 1914. Serial No. 873,137.

To all whom it may concern: Be it known that I, MORDUCH L. ,KAPLAN, a citizen of the United States, and a resident of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements 'in Galvanic Cells, of which the following is a specification.

This invention relates to galvanic cells-of the Leclanch typeconsisting of a negative zinc pole, a positive carbon pole, an electrolyte containing ammonium chlorid or other ammonium salts, and the like and a depolarizing mass comprising powdered graphite or other form of conducting carbon, incorporated with an oxid of manganese of peculiar qualities and high efficiency as a depolarizing agent and relates in particular to dry cells or batteries, especially the form known as the miniature dry cell; as more particularly hereinafter described in detail and set forth in the appended claims.

It is customary to make use of manganese.

peroxid as a depolarizing agent in-cells of the Leclanch type, the natural peroxid such as pyrolusite commonly being used for the purpose, although an artificial form of the peroxid containing water of hydration which form is obtained by precipitation, with reagents, of the peroxid from solutions of manganese compounds also has been employed to some extent. While both of these materials are more or less useful in the manufacture of large stationary units, they are not as well adapted for use in the. roduction of the miniature dry cell. he natural mineral manganese is diflicult to grind to as fine a degree as is desired and ,the precipitated manganese material, although finely divided, is commonly very bulky; due no doubt to its water of hydra-' tion, so that depolarizing material, in a sufiicient quantity can scarcely be crowded into the small space available for the depolarizing element. drate water lowers the percentage of active oxygen. Thus while these materials may be'used in the larger or stationary units of the Leclanch type, they are not well adapt-' ed for the production of the very compact form'of dry cell, known as miniature, which is used very largely for making pocket flash lights and the like which necessarily must have high depolarizing efliciency in order to Furthermore the 'hysatisfactory performsatisfactory depolarizing action is secured and whereby it becomes possible, due to the high specific gravity of the material in its preferred form, to concentrate and compact finely-divided graphite or other suitable form of conducting carbon with such a quantity of the depolarizing compound that long life of the cell is assured and a high cur rent output is eflectively developed over a relatively long period of time.

Patented Apr. 3, rear.

While ordinarily, the presence of lower I oxids of manganese is undesirable, 'it' appears under the present circumstances that\ a lower oxid in some form is desirableor essential to the operative qualities of the product and it further appears that manganese oxld in a lower form of oxidation in some peculiar form of combination with the pound. Thus itbecomes possi le to use :a

manganese depolarizer of a density-heretofore thought to. be unfeasible, especially from the standpoint of'the artificially prepared product, because the catalytic or analogous action of the loweroxid of manganese. serves in some peculiar way to conveyoxygen fromthe inner to the outer portions of the particle, or to act in some equivalent manner and thus enables the complete or substantially complete utilization of the manganese depolarizing compound in a manner most advantageous for the type known as the miniature dry cell.

A form of manganese depolarizer which is adapted to be used in accordance with the present invention may be prepared according to the following illustrative example which represents my invention in its preferred embodiment. Manganous carbonate MniCO is heated in the presence of air or oxygen in order to oxidize the manganous carbonate to a considerable degree and the oxidation is then completed up to the desired measure of oxidation, by the action of a powerful oxidizing agent such as a solution of permanganate of potash or soda. The degree of oxidation by the action of air varies considerably according to circumstances and consequently the amount of permanganate or other oxidizing agent such as would be used may be determined by chemical control; that is to say, the air-oxidized material is analyzed and sufficient permanganate employed to raise the degree of oxidation to the required point. As to this final degree of exit-lotion, l not limit myself to any precise proportions, but

have found a roduct containing an J 3.

mately ten molecules of roxid to one molecule of m '13 ions oxid is well adapted for the pur e, the formula corresponding to sucn. compound being10MnO MnO. Although as indicated it would appear that the manganese peroxid and the manganous oxid are in combination, it is difficult to state just what the form of combination is and hence 1 content myself with setting forth the foregoing formula merely as illustrative, and as representing a new class of the higher oxide of manganese seemingly containing a catalytic material which enablesthe action of autooxidation or auto-reduction to be consummated. Also, it is possible to prepare such 'a compound in a practically anhydrous condition and in this form it appears that the reactions involved progress with great regularity and uniformity, apparently enabling oxygen to be brought from the inner part of the fragment or particle to its surface, where the process of depolarization takes place, thus bringing about the full measure of particle or fragment reduction of such compact anhydrous manganese material.

In making up the miniature dry cell the following conditions generally obtain'when using the present form of material. The manganese depolarizing compound is mixed with finely-dividedgraphite and after preferably being moistened with the electrolyte is formed into a compact blocs or mass by molding under pressure around a rod or penoil of carbon. The carbon electrode with its enveloping mass of shaped or molded'depolarizing and conducting material supported by and in electrical contact with it is wrapped in. a tissue such as cloth and is placed pendant in a zinc container forming the negative electrode and which also serves to hold a viscous, gelatinous or pasty mass serving as the electrolyte and commonly containing ammonium chlorid. The use of an electrolyte or exciting composition of this consistency is of especial utility when a dense polarizer of this character is employed. The top of the zinc container is then suitably sealed or plugged;

Owing to the fact that the manganese material prepared in this manner has little or no conducting power for the electric current it is necessary to use a substantial amount of graphite or similar conducting material in order to prevent so high an internal resistance that the output of the battery is affected and an excess of the manganese material over the graphite preferably should be used; that is, the amount of the graphite in fact preferably exceeding the ratio of 3 2 and to that end I prefer to employ finelydivided or powdered graphite in the proportion of ten'parts of graphite to seventeen parts of the manganese compound, which i find in the case of the miniature dry cell enables the internal resistance of the cell to foe such. that conjunction with the efiective depolarizing action of the compact mano material very eficient results are sel-irther precaution which should be especially when concerned with the manufacture of the miniature dry cell is that of extracting the prepared manganese depolarizing compound with dilute acid, so as to remove traces of saltsand possibly manganous bodies, as manganous oxid etc. The acid extracted material has been found by me to be more satisfactory from the standpoint of absence of local action. If deterioration occurs on standing in thecase of the miniature dry cell the loss in current output is speedily noticed and it is important in the case of these small dry cells to take the precaution that the depolarizer remains in good condition in the finished cell when standing unused as when in storage over a long period of time, for, owing to the smallness of the electrode and the hard service expected of the miniature cell, any deterioration by local. action is speedily felt. The acid extraction removes manganous oxid or other bodies which probably, have a deteriorating effect enabling a product to be obtained which does not possess the objectionable feature referred to above, and which appears as a compact, finelydivided substantially anhydrous higher oxid of manganese product capable of undergoing effective depolarizing reduction throughout its mass. 1

While I have referred particularly to a highly reactive depolarizer of anhydrous nature I do not limit myself thereto, but may employ somewhat hydrated products, provided the material is of such specific gravity as not to undesirably influence the electrical output.

The accompanying drawing shows in vertical section the organization of the battery of the present invention. In the drawing 1 eagues enceof a thickening agent. 6 is insulating material which is placed in the bottom of the zinc container, and a ring of rubber 7 serves to insulate the carbon rod and keep the depolarizing mass from contact with the walls of the container. 8 is a mass of waxy sealing material. The active manganese depolarizing material is of such a compact nature that the depolarizing mixture occupies a relatively small amount of space so that the carbon rod is spaced only at ashort distance from the walls of the zinc electrode, thereby reducing internal resistance to a minimum.

, What I- claim is:

1. In a dry battery, a depolarizing agent comprising a mixture of finely-dividedacarboil and incorporated but chemically uncombined therewith a larger proportion of manganese depolarizing material comprising a roasted compact substantially anhydrous artificial higher oxid of manganese product,

. substantially free from water-soluble bodies capable of causing local action and having less combined oxygen than corresponds to the formula MnO 2.'In a battery of the Leclanch type, a depolarizing agent comprising finely-divided graphite and therewith incorporated manganese depolarizing material comprising an ignited substantially. anhydrous artificial higher oxid of manganese substantially free from water-soluble salts capable of causing local action; said oxid of manganese being present in the proportion of at least three parts to two parts of graphite.

3. In a miniature dry battery, .a depolarizing agent comprising about ten :parts of finely-divided carbon and about seventeen parts of. substantially anhydrous artificial manganese peroxid substantiallyfree from bodies causing local action;

4. In a dry battery, a depolarizing agent comprising a mixture of finely-divided car -bon and an excess of roasted substantially anhydrous and compact artificial hi her oxid of manganese substantially free rom uncombined with said carbon and having less combined oxygen than corresponds to the formula MnO I 5. In a galvanic cell, a depolarizing agent adapted for use in miniature batteries comprising finelyrdivided carbon and therewithadmixed manganese depolarizin material comprising a roasted compact su tantially anhydrous artificial higher oxid of manganese product and some lower oxid of manganese.

6. In a dry battery, a depolarizing agent adapted for use in miniature batteries, which agent comprises finely-divided graphite and bodies causing locai action,'-being chemically therewith-incorporated manganese depo1ar-' izing material comprising roasted substantially anhydrous artificial, higher oxid of manganese compound havingapproximatcly the formula 10MnO,,.MnO.

7. In a dry battery, a depolarizing agent comprising finely-divided carbon and roasted substantially anhydrous artificial manganese peroxid and a lower oxid of manganese.

8. n a dry battery of the miniature type a depolarizing agent comprising finely-divided carbon. and roasted substantially anhydrous and compact artificial manganese a peroxid uncombined therewith.

higher oxid depolarizing material containing a modicum of a manganous body and having a substantiall greater utilizable depolarizing capacity t an natural manganese peroxid but having less combined oxygenthan corresponds to the formula MnO Signed at New-York city, in the county of New York and State of New York, this 18th day of November, A. D. 1914, V MORDUCH L. KAPLAN.

Witnesses: A

ARTHUR MARION, CHAS. C. GILL. 

